Modem semiconductor processing involves the precision growth of oxide layers across wafers of semiconductor material having diameters as large as 30 cm. During the growth of oxide layers, the entire wafer, or often a large number of wafers, is maintained at a regulated temperature within a furnace. Similarly, the composition of gases within the furnace is controlled. Standard procedure is either to maintain a nearly uniform temperature profile over the region of the furnace containing the wafer or wafers undergoing processing or to provide zonal radiative heating of the wafer. In some cases, the control of temperature may be critical for achieving chemical reaction at the requisite rate.
Other applications require the rapid and precision control of the temperature of a boundary or interface between one medium, which may be a solid or a liquid, and an ambient environment, which may be a second medium such as a liquid or a gas. One such application is microchemistry where precision control of chemical or biological processes is required in some instances.